In recent years, the following work vehicle has been proposed in a field of a work vehicle configured to carry out various operations while running a traveling machine for purpose of improving work efficiency and reducing workload. That is, a work vehicle configured to carry out various operations by unmanned traveling or by so-called autonomous traveling without a driver getting on board.
Examples of such a work vehicle include one that autonomously travels using a global navigation satellite system (GNSS), one that autonomously travels using sensors such as a physically contact sensor and optical sensor, and one that autonomously travels using images captured by an image-capturing device.
For example, Patent Literature 1 discloses a traveling-controlling device for an autonomously-traveling work vehicle, as an example of a device included in the work vehicle configured to use images to travel autonomously. The traveling-controlling device herein is configured to control a work vehicle to travel along a working boundary between a worked area and non-worked area. With respect to distance images obtained by processing images captured by a stereoscopic camera mounted on the vehicle, a unit included in the traveling-controlling device is configured to detect a distance step due to the working boundary based on changes in differential value obtained by differentiating distance data. The traveling-controlling device also includes a unit configured to calculate a straight line approximating the working boundary based on detection points of the distance step. Furthermore, the traveling-controlling device includes a unit configured to correct orientation of the vehicle based on the data of the straight line approximating the working boundary and to control a steering system so as to travel along the working boundary.